<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Exception.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @category   Zend
 * @package    Zend
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Exception extends Exception {
	/**
	 * @var null|Exception
	 */
	private $_previous = null;
	
	/**
	 * Construct the exception
	 *
	 * @param  string $msg
	 * @param  int $code
	 * @param  Exception $previous
	 * @return void
	 */
	public function __construct($msg = '', $code = 0, Exception $previous = null) {
		if (version_compare ( PHP_VERSION, '5.3.0', '<' )) {
			parent::__construct ( $msg, ( int ) $code );
			$this->_previous = $previous;
		} else {
			parent::__construct ( $msg, ( int ) $code, $previous );
		}
	}
	
	/**
	 * Overloading
	 *
	 * For PHP < 5.3.0, provides access to the getPrevious() method.
	 *
	 * @param  string $method
	 * @param  array $args
	 * @return mixed
	 */
	public function __call($method, array $args) {
		if ('getprevious' == strtolower ( $method )) {
			return $this->_getPrevious ();
		}
		return null;
	}
	
	/**
	 * String representation of the exception
	 *
	 * @return string
	 */
	public function __toString() {
		if (version_compare ( PHP_VERSION, '5.3.0', '<' )) {
			if (null !== ($e = $this->getPrevious ())) {
				return $e->__toString () . "\n\nNext " . parent::__toString ();
			}
		}
		return parent::__toString ();
	}
	
	/**
	 * Returns previous Exception
	 *
	 * @return Exception|null
	 */
	protected function _getPrevious() {
		return $this->_previous;
	}
}
